PRODUCTION OF PREFORM FOR OPTICAL FIBER

摘要

PURPOSE:To provide a process for producing an optical fiber preform effective for preventing the damage such as cracking in the thermal treatment such as annealing and drawing of the preform. CONSTITUTION:A porous glass preform formed by depositing silica soot generated by the flame-hydrolysis of a glass raw material on the outer circumference of a starting glass rod is dehydrated and sintered to obtain an optical fiber preform. In the above process, dummy glass rod made of quartz glass is welded to one or both ends of the starting glass rod and the silica soot is deposited on the starting glass rod while preventing the deposition of silica soot on the dummy glass rod welded to the starting rod.